1. Field of the Invention
This invention relates to a three-terminal type capacitor, a three-terminal type capacitor array, and an assembly for removing jamming signals incorporating the three-terminal capacitor and/or array. The capacitor and capacitor array of this invention are suited for removing jamming signals generated by the electric circuit which includes the capacitor or jamming signals received from other electric circuits, such as in electrical appliances like television sets.
2. Description of the Prior Art
Recently, as digital circuits in electrical appliances become smaller in size and greater in function the parts used in them for removing jamming signals must also be smaller in size and have a superior ability to remove jamming signals. As a representative example of prior art systems for removing jamming signals, the assembly of FIG. 1 shows a disk-shaped feed-through capacitor 5 comprising a signal electrode 1, a dielectric 2, and a ground electrode 3. As shown in FIG. 2, feed-through capacitor 5 is attached to the input/output terminals of a metal shield case 4 incorporating electric circuits.
In this type of conventional jamming signal removal device, the spacing of signal lines is determined by the size of the feed-through capacitor 5. Therefore, when the number of signal lines increases the number of feed-through capacitors 5 contained in the metal shield case 4 increases and the size of the jamming signal assembly becomes very large. Further, the manufacturing efficiency of the jamming signal assembly is reduced due to the increased number of feed-through capacitors because each feed-through capacitor 5 must be individually soldered to metal shield case 4.
Japanese Patent Publication No. 4-32170, represented by the drawing of FIG. 3, discloses a reduced size assembly for removing jamming signal comprising a terminal-strip mounting a printed type capacitor on a metal shield case. The terminal strip is made by sequentially forming a first electrode layer 12, which is a ground electrode of the capacitor, on a ceramic substrate 11 having a penetration hole 15, and a dielectric layer 13. A second electrode layer 14 is soldered on dielectric layer 13 and around penetration hole 15, and a pin terminal 16 is inserted into the penetration hole 15. The terminal strip is fixed in a metal shield case (not shown) by a protrusion 17 of the metal shield case. Although the terminal strip of FIG. 3 can be reduced in size, the performance of jamming signal removal is reduced because the dielectric layer 13 is not wrapped in first electrode layer 12 structurally.
The devices described above provide important advantages in operation. Nevertheless, none of these devices provide the important advantage of both superior jamming signal removal in a small size assembly.